Resource Type

118 Matching Results

Results open in a new window/tab.

Generalized molecular solvation in non-aqueous solutions by a single parameter implicit solvation scheme (open access)

Generalized molecular solvation in non-aqueous solutions by a single parameter implicit solvation scheme

Article presenting a systematic parametrization protocol for the Self-Consistent Continuum Solvation (SCCS) model resulting in optimized parameters for 67 non-aqueous solvents. The parametrization is based on a collection of ≈6000 experimentally measured partition coefficients, which were collected in the Solv@TUM database presented here. The accuracy of the optimized SCCS model is comparable to the well-known universal continuum solvation model (SMx) family of methods, while relying on only a single fit parameter and thereby largely reducing statistical noise.
Date: August 3, 2018
Creator: Acree, William E. (William Eugene); Hille, Christoph; Ringe, Stefan; Deimel, Martin; Kunkel, Christian; Reuter, Karsten et al.
System: The UNT Digital Library
Modeling Soil/Radionuclide Removal for Yucca Mountain Biosphere Dose Assessments (open access)

Modeling Soil/Radionuclide Removal for Yucca Mountain Biosphere Dose Assessments

None
Date: December 5, 2000
Creator: Aguilar, R. & Smith, A. J.
System: The UNT Digital Library
Determining thermal diffusivity and defect attributes in ceramic matrix composites by infrared imaging. (open access)

Determining thermal diffusivity and defect attributes in ceramic matrix composites by infrared imaging.

Ceramic matrix composites are being developed for numerous high temperature applications, including rotors and combustors for advanced turbine engines, heat exchanger and hot-gas filters for coal gasification plants. Among the materials of interest are silicon-carbide-fiber-reinforced-silicon-carbide (SiC{sub (f)}/SiC), silicon-carbide-fiber-reinforced-silicon-nitride (SiC{sub (f)}/Si{sub 3}N{sub 4}), aluminum-oxide-reinforced-alumina (Al{sub 2}O{sub 3(f)}/Al{sub 2}O{sub 3}), etc. In the manufacturing of these ceramic composites, the conditions of the fiber/matrix interface are critical to the mechanical and thermal behavior of the component. Defects such as delaminations and non-uniform porosity can directly effect the performance. A nondestructive evaluation (NDE) method, developed at Argonne National Laboratory has proved beneficial in analyzing as-processed conditions and defect detection created during manufacturing. This NDE method uses infrared thermal imaging for fill-field quantitative measurement of the distribution of thermal diffusivity in large components. Intensity transform algorithms have been used for contrast enhancement of the output image. Nonuniformity correction and automatic gain control are used to dynamically optimize video contrast and brightness, providing additional resolution in the acquired images. Digital filtering, interpolation, and least-squares-estimation techniques have been incorporated for noise reduction and data acquisition. The Argonne NDE system has been utilized to determine thermal shock damage, density variations, and variations in fiber coating in a full …
Date: December 5, 1997
Creator: Ahuja, S.; Ellingson, W. A.; Koehl, E. R. & Stuckey, J.
System: The UNT Digital Library
MAP training: combining meditation and aerobic exercise reduces depression and rumination while enhancing synchronized brain activity (open access)

MAP training: combining meditation and aerobic exercise reduces depression and rumination while enhancing synchronized brain activity

This article discusses the efficacy of mental and physical (MAP) training in improving symptoms of depression and rumination in individuals with major depressive disorder (MDD).
Date: October 5, 2015
Creator: Alderman, Brandon L.; Olson, Ryan L.; Brush, Christopher J. & Shors, Tracey J.
System: The UNT Digital Library
Gene by Disease Interaction on Orbitofrontal Gray Matter in Cocaine Addiction (open access)

Gene by Disease Interaction on Orbitofrontal Gray Matter in Cocaine Addiction

Chronic cocaine use has been associated with structural deficits in brain regions having dopamine receptive neurons. However, the concomitant use of other drugs and common genetic variability in monoamine regulation present additional structural variability. We therefore examined variations in gray matter volume (GMV) as a function of lifetime drug use and the monoamine oxidase A (MAOA) genotype in cocaine use disorders (CUD) and healthy controls.
Date: December 5, 2010
Creator: Alia-Klein, N.; Alia-Klein, N.; Parvaz, M. A.; Woicik, P. A.; Konova, A.; Maloney, T. et al.
System: The UNT Digital Library
Radiation damage of a glass-bonded zeolite waste form using ion irradiation. (open access)

Radiation damage of a glass-bonded zeolite waste form using ion irradiation.

Glass-bonded zeolite is being considered as a candidate ceramic waste form for storing radioactive isotopes separated from spent nuclear fuel in the electrorefining process. To determine the stability of glass-bonded zeolite under irradiation, transmission electron microscope samples were irradiated using high energy helium, lead, and krypton. The major crystalline phase of the waste form, which retains alkaline and alkaline earth fission products, loses its long range order under both helium and krypton irradiation. The dose at which the long range crystalline structure is lost is about 0.4 dpa for helium and 0.1 dpa for krypton. Because the damage from lead is localized in such a small region of the sample, damage could not be recognized even at a peak damage of 50 dpa. Because the crystalline phase loses its long range structure due to irradiation, the effect on retention capacity needs to be further evaluated.
Date: December 5, 1997
Creator: Allen, T. R. & Storey, B. G.
System: The UNT Digital Library
QMDS: A File System Metadata Management Service Supporting a Graph Data Model-based Query Language (open access)

QMDS: A File System Metadata Management Service Supporting a Graph Data Model-based Query Language

None
Date: December 5, 2011
Creator: Ames, S; Gokhale, M B & Maltzahn, C
System: The UNT Digital Library
Continuum description of avalanches in granular media. (open access)

Continuum description of avalanches in granular media.

A continuum theory of partially fluidized granular flows is proposed. The theory is based on a combination of the mass and momentum conservation equations with the order parameter equation which describes the transition between flowing and static components of the granular system. We apply this model to the dynamics of avalanches in chutes. The theory provides a quantitative description of recent observations of granular flows on rough inclined planes (Daerr and Douady 1999): layer bistability, and the transition from triangular avalanches propagating downhill at small inclination angles to balloon-shaped avalanches also propagating uphill for larger angles.
Date: December 5, 2000
Creator: Aranson, I. S. & Tsimring, L. S.
System: The UNT Digital Library
Spatiotemporal dynamics of a shallow fluidized bed. (open access)

Spatiotemporal dynamics of a shallow fluidized bed.

An experimental and theoretical study of the dynamics of an air-fluidized thin granular layer is presented. Near the threshold of instability, the system exhibits critical behavior with remarkably long transient dynamics. Above the threshold of fluidization the system undergoes a Hopf bifurcation as the layer starts to oscillate at a certain frequency due to a feedback between the layer dilation and the airflow rate. Based on our experimental data, we formulate a the simple dynamical model which describes the transition in a shallow fluidized bed.
Date: December 5, 2000
Creator: Aranson, I. S.; Tsimring, L. S. & Clark, D. K.
System: The UNT Digital Library
Exchange-spring behavior in epitaxial hard/soft magnetic bilayer films. (open access)

Exchange-spring behavior in epitaxial hard/soft magnetic bilayer films.

We present results on the magnetic reversal process in epitaxial Sm-Co (1{bar 1}00)/TM (TM = Fe, Co) bilayer films prepared via magnetron sputtering onto Cr-buffered single-crystal MgO substrates. The magnetically hard Sm-Co films have 20-T uniaxial anisotropy and coercivities >3 T at room temperature. The magnetization of the soft layer is pinned at the interface to the hard-magnet layer and switches reversibly as expected for an exchange-spring magnet. With increasing soft layer thickness, the coercive field of the hard layer becomes significantly less than that of a single layer. We also present numerical solutions of a one-dimensional model that provide the spin configuration for each atomic layer. Comparison of the experimental results with the model simulations indicates that the exchange-spring behavior of our bilayer films can be understood from the intrinsic parameters of the hard and soft layers.
Date: December 5, 1997
Creator: Bader, S. D.; Fullerton, E. E.; Grimsditch, M.; Jiang, J. S. & Sowers, C. H.
System: The UNT Digital Library
Growth and characterization of epitaxial fcc Fe wedges on diamond (100). (open access)

Growth and characterization of epitaxial fcc Fe wedges on diamond (100).

Epitaxial Fe wedges with a thickness gradation from 0--20 {angstrom} were grown on diamond(100) at room temperature, subsequently annealed, and investigated with reflection high-energy electron diffraction and the surface magneto-optical Kerr effect. The results indicate that for <5 monolayer thicknesses the Fe grows on C(100) as smooth, epitaxial fcc films, which are not ferromagnetic, but that thicker films undergo a transition to become rough and the ordinary bcc ferromagnetic phase.
Date: December 5, 1997
Creator: Bader, S. D.; Keavneu, D. J.; Keune, W.; Li, D. & Pearson, J.
System: The UNT Digital Library
First use of a laser-driven polarized H/D target at the IUCF cooler. (open access)

First use of a laser-driven polarized H/D target at the IUCF cooler.

The HERMES Laser-Driven Target Task Force (Argonne, Erlangen and Illinois) is charged with developing a polarized H/D target for use in the HERA ring at DESY. Rapid progress was made in the beginning of 1996, leading us to the decision to test the target in a realistic experimental environment. In particular, polarizations of 0.6 and flows above 10{sup 18} atoms{center_dot}s{sup {minus}1} have been achieved on the bench. The laser-driven target and a simple detector system are currently installed in Cooler storage ring at the Indiana University Cyclotron Facility in order to test its applicability to nuclear physics experiments. Target polarizations are being measured using the {rvec H}(p, p) and {rvec D}(p, p) reactions. Initial tests were reasonably successful and the target is well along toward becoming viable for nuclear physics.
Date: December 5, 1997
Creator: Bailey, K.; Brack, J.; Cadman, R. V.; Cummings, W. J.; Fedchak, J.; Fox, B. et al.
System: The UNT Digital Library
Search for a Light Higgs Boson at BaBar (open access)

Search for a Light Higgs Boson at BaBar

We search for evidence of a light Higgs boson (A{sup 0}) in the radiative decays of the narrow {Upsilon}(3S) resonance: {Upsilon}(3S) {yields} {gamma}A{sup 0}, where A{sup 0} {yields} invisible or A{sup 0} {yields} {mu}{sup +}{mu}{sup -}. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. We find no evidence for such processes in a sample of 122 x 106 {Upsilon}(3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the product of the branching fractions {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} invisible) at (0.7-31) x 10{sup -6} in the mass range mA{sup 0} {le} 7.8 GeV, and on the product {Beta}({Upsilon}(3S) {yields} {gamma}A{sup 0}) x {Beta}(A{sup 0} {yields} {mu}{sup +}{mu}{sup -}) at (0.25-5.2) x 10{sup -6} in the mass range 0.212 {le} mA{sup 0} {le} 9.3GeV. We also set a limit on the dimuon branching fraction of the recently discovered {eta}{sub b} meson {Beta}({eta}{sub b} {yields} {mu}{sup +}{mu}{sup -}) < 0.8% at 90% C.L. The results are preliminary.
Date: December 5, 2011
Creator: Banerjee, Swagato
System: The UNT Digital Library
Fusion target design (open access)

Fusion target design

Most detailed fusion target design is done by numerical simulation using large computers. Although numerical simulation is briefly discussed, this lecture deals primarily with the way in which basic physical arguments, driver technology considerations and economical power production requirements are used to guide and augment the simulations. Physics topics discussed include target energetics, preheat, stability and symmetry. A specific design example is discussed.
Date: December 5, 1978
Creator: Bangerter, R.O.
System: The UNT Digital Library
Measurement of the CKM Angles at BaBar And Belle (open access)

Measurement of the CKM Angles at BaBar And Belle

The primary goal of the BaBar and Belle experiments is to overconstrain the CKM Unitarity Triangle. Measurements of the angles of this triangle, known as {beta}, {alpha}, and {gamma} (or {phi}{sub 1}, {phi}{sub 2}, and {phi}{sub 3}) give insight into the Standard Model description of CP violation in the quark sector. BaBar and Belle have recorded almost 1 ab{sup -1} combined, and have measured {beta} to high precision. Measurements of {alpha} and {gamma} are less precise at present, but both experiments are rapidly accumulating data and developing new analysis techniques, and measurements of these angles will continue to provide useful constraints on the Standard Model description of CP violation in the years to come.
Date: December 5, 2007
Creator: Barlow, Nick
System: The UNT Digital Library
Measurement of {Delta}m{sub d} using a probability based same-side tagger applied to lepton + vertex events (open access)

Measurement of {Delta}m{sub d} using a probability based same-side tagger applied to lepton + vertex events

None
Date: December 5, 2000
Creator: Bauer, Gerry
System: The UNT Digital Library
Adaptive learning: toward an intentional model for learning process guidance based on learner’s motivation (open access)

Adaptive learning: toward an intentional model for learning process guidance based on learner’s motivation

Article describes how, the goal of ITS is to support learning content, activities, and resources, adapted to the specific needs of the individual learner and influenced by learner’s motivation. This research proposes an intentional model that adopts Map formalism to support personalized learning guidance by considering learner’s motivation.
Date: December 5, 2022
Creator: Bayounes, Walid; Saâdi, Bayoudh Ines & Kinshuk
System: The UNT Digital Library
Structure and electrochemical potential simulation for the cathode material Li(1+x)V(3)O(8). (open access)

Structure and electrochemical potential simulation for the cathode material Li(1+x)V(3)O(8).

The structure and electrochemical potential of monoclinic Li{sub 1+x}V{sub 3}O{sub 8} were calculated within the local-density-functional-theory framework by use of plane-wave-pseudopotential methods. Special attention was given to the compositions 1+x=1.2 and 1+x=4, for which x-ray diffraction structure refinements are available. The calculated low-energy configuration for 1+x=4 is consistent with the three Li sites identified in x-ray diffraction measurements and predicts the position of the unobserved Li. The location of the tetrahedrally coordinated Li in the calculated low-energy configuration for 1+x=1.5 is consistent with the structure measured by x-ray diffraction for Li{sub 1.2}V{sub 3}O{sub 8}. Calculations were also performed for the two monoclinic phases at intermediate Li compositions, for which no structural information is available. Calculations at these compositions are based on hypothetical Li configurations suggested by the ordering of vacancy energies for Li{sub 4}V{sub 3}O{sub 8} and tetrahedral site energies in Li{sub 1.5}V{sub 3}O{sub 8}. The internal energy curves for the two phases cross near 1+x=3. Predicted electrochemical potential curves agree well with experiment.
Date: December 5, 1997
Creator: Benedek, R.; Thackeray, M. M. & Yang, L. H.
System: The UNT Digital Library
A quantum mechanical equivalent photon spectrum for heavy ion reactions (open access)

A quantum mechanical equivalent photon spectrum for heavy ion reactions

Radioactive nuclear beams are rapidly coming to the fore as an important alternative to traditional measurements in nuclear astrophysics. Radioactive nuclei are scattered off the strong electromagnetic fields of a heavy ion, such as lead, providing an independent measurement of electromagnetic cross sections that are difficult to measure otherwise. In this paper, we examine the corrections to the semi-classical ``equivalent photon spectrum`` used to analyze these experiments, and derive an improved spectrum, valid in the long wavelength limit, that includes the effects of the size of the heavy ion, the non-zero longitudinal momentum transfer required by kinematics, and the response of the target nucleus to be off-shell photon.
Date: December 5, 1995
Creator: Benesh, C.J.; Hayes, A.C. & Friar, J.L.
System: The UNT Digital Library
Modern Scientific Visualization is more than Just Pretty Pictures (open access)

Modern Scientific Visualization is more than Just Pretty Pictures

While the primary product of scientific visualization is images and movies, its primary objective is really scientific insight. Too often, the focus of visualization research is on the product, not the mission. This paper presents two case studies, both that appear in previous publications, that focus on using visualization technology to produce insight. The first applies"Query-Driven Visualization" concepts to laser wakefield simulation data to help identify and analyze the process of beam formation. The second uses topological analysis to provide a quantitative basis for (i) understanding the mixing process in hydrodynamic simulations, and (ii) performing comparative analysis of data from two different types of simulations that model hydrodynamic instability.
Date: December 5, 2008
Creator: Bethel, E Wes; Rubel, Oliver; Wu, Kesheng; Weber, Gunther; Pascucci, Valerio; Childs, Hank et al.
System: The UNT Digital Library
Modified ring stretch tensile testing of Zr-1Nb cladding. (open access)

Modified ring stretch tensile testing of Zr-1Nb cladding.

In a round robin effort between the US Nuclear Regulatory Commission, Institut de Protection et de Surete Nucleaire in France, and the Russian Research Centre-Kurchatov Institute, Argonne National Laboratory conducted 16 modified ring stretch tensile tests on unirradiated samples of Zr-1Nb cladding, which is used in Russian VVER reactors. Tests were conducted at two temperatures (25 and 400 C) and two strain rates (0.001 and 1 s{sup {minus}1}). At 25 C and 0.001 s{sup {minus}1}, the yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE), and total elongation (TE) were 201 MPa, 331 MPa, 18.2%, and 57.6%, respectively. At 400 C and 0.001 s{sup {minus}1}, the YS, UTS, UE, and TE were 109 MPa, 185 MPa, 15.4%, and 67.7%, respectively. Finally, at 400 C and 1 s{sup {minus}1}, the YS, UTS, UE, and TE were 134 MPa, 189 MPa, 18.9%, and 53.4%, respectively. The high strain rate tests at room temperature were not successful. Test results proved to be very sensitive to the amount of lubrication used on the inserts; because of the large contact area between the inserts and specimen, too little lubrication leads to significantly higher strengths and lower elongations being reported. It is also important to …
Date: December 5, 1997
Creator: Billone, M. C.; Chung, H. M.; Cohen, A. B.; Majumdar, S.; Neimark, L. A. & Ruther, W. E.
System: The UNT Digital Library
A Flexure-Based Tool Holder for Sub-(micro)m Positioning of a Single Point Cutting Tool on a Four-axis Lathe (open access)

A Flexure-Based Tool Holder for Sub-(micro)m Positioning of a Single Point Cutting Tool on a Four-axis Lathe

A tool holder was designed to facilitate the machining of precision meso-scale components with complex three-dimensional shapes with sub-{micro}m accuracy on a four-axis lathe. A four-axis lathe incorporates a rotary table that allows the cutting tool to swivel with respect to the workpiece to enable the machining of complex workpiece forms, and accurately machining complex meso-scale parts often requires that the cutting tool be aligned precisely along the axis of rotation of the rotary table. The tool holder designed in this study has greatly simplified the process of setting the tool in the correct location with sub-{micro}m precision. The tool holder adjusts the tool position using flexures that were designed using finite element analyses. Two flexures adjust the lateral position of the tool to align the center of the nose of the tool with the axis of rotation of the B-axis, and another flexure adjusts the height of the tool. The flexures are driven by manual micrometer adjusters, each of which provides a minimum increment of motion of 20 nm. This tool holder has simplified the process of setting a tool with sub-{micro}m accuracy, and it has significantly reduced the time required to set a tool.
Date: December 5, 2005
Creator: Bono, M J & Hibbard, R L
System: The UNT Digital Library
Local Two-Photon Couplings and the J=0 Fixed Pole in Real and Virtual Compton Scattering (open access)

Local Two-Photon Couplings and the J=0 Fixed Pole in Real and Virtual Compton Scattering

The local coupling of two photons to the fundamental quark currents of a hadron gives an energy-independent contribution to the Compton amplitude proportional to the charge squared of the struck quark, a contribution which has no analog in hadron scattering reactions. We show that this local contribution has a real phase and is universal, giving the same contribution for real or virtual Compton scattering for any photon virtuality and skewness at fixed momentum transfer squared t. The t-dependence of this J = 0 fixed Regge pole is parameterized by a yet unmeasured even charge-conjugation form factor of the target nucleon. The t = 0 limit gives an important constraint on the dependence of the nucleon mass on the quark mass through the Weisberger relation. We discuss how this 1=x form factor can be extracted from high energy deeply virtual Compton scattering and examine predictions given by models of the H generalized parton distribution.
Date: December 5, 2008
Creator: Brodsky, Stanley J.; Llanes-Estrada, Felipe J. & Szczepaniak, Adam P.
System: The UNT Digital Library
New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 - New Physics Working Group (open access)

New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 - New Physics Working Group

We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high p{sub T} leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 11-29 June, 2007).
Date: December 5, 2011
Creator: Brooijmans, Gustaaf H.; Delgado, A.; Dobrescu, Bogdan A.; Grojean, C.; Narain, Meenakshi; Alwall, Johan et al.
System: The UNT Digital Library